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This is a “live cyclone coverage” that started from May 24 and will end on June 13. From June 13, normal articles of Pakistan Weather Portal (PWP) will resume.

More Western winds for Punjab

Turbat sizzles at 50°C again

Pre-Monsoon activty in Karachi continues

Chances of depression in the Arabian sea still persists

Pakistan Weather Background

Storm to hit Gujarat according to BBC weather

*A weak western disturbance would affect Northern Pakistan.

*Heat wave to persist in parts of Balochistan and Sindh.

*Tropical cyclone “Keila” may affect lower Sindh.

Western disturbance and Northern Pakistan

A weak westerly wave will approach Pakistan on May 31 and leave for India on June 3. Under its influence light to moderate rainfall with strong gusty winds likely. Lahore, Islamabad, Peshawar and adjoining areas all expected to get rains during this period. No major weather expected other than that, but Pakistan Weather Portal will keep an eye on these dust storms which are deadly in this month of year especially in Punjab. Following is the rain forecast from Pakistan Weather Portal (PWP) for some cities;

In Lahore, Lahoris will have a cloudy start to the new month, light rainfall will occur on June 1 and during the evening it will become moderate with strong winds. Rain will continue till June 2.

In Islamabad, the capital will have thunder showers with strong winds will start from May 31 and continue till June 2.

In Peshawar, light rainfall with occasional gaps till June 2.

In Multan, some rainfall with stray thunder till June 2.

Overall these rains will continue till June 3 and after that they will start entering Kashmir, India.

Heat wave and southern Pakistan

Temperatures during first week of June

The seasonal heating continues in Pakistan especially in Sindh where temperatures are above 47 °C. Temperatures have touched 50°C in Turbat while 49°C in Sibbi, Balochistan on May 31.

During the coming days temperatures will decrease in Punjab, Khyber, north-east Balochistan due to westerly wave. But this time these western winds will not cause temperatures to decrease in Sindh and temperatures are expected to rise there.

Tropical depression ARB 01 – Scenario still holds

The expected storm is likely to make landfall in Balcohistan as of May 31

As of May 31, a low pressure should have formed in the Arabian sea but still an Upper air cyclonic circulations persist that are expected to enhance monsoon activity over western India especially Kerala, where heavy to very heavy monsoon showers likely. There are two things that could happen to this system;

Most model do not forecast the upper air cyclonic circulation in the Arabian sea near western Indian coast to intensify. If that’s the case then these circulations will fizzle out near Goa and Mumbai but could cause some heavy rainfall there.

Few suggest it will intensify into a low pressure and then into a depression at least if not a cyclonic storm. If that is the case then it’s either Oman or Pakistan or India.

Pre-monsoon clouds will keep entering Karachi during the next few days, fast winds are also likely, No major weather conditions likely.

Monsoon Update 2011

Monsoon arrives in India early

Heavy rainfall likely in many parts of India

India

Thunder towers are visible indicating that storm is gainig energy as of May 31

The southwest monsoon, which arrived in Kerala on May 30, has advanced to some more parts to the south of Bay of Bengal, remaining parts of Andaman Sea and parts of east central Bay of Bengal.

Widespread monsoon rainfall would occur over Lakshadweep and Kerala till June 3. Fairly widespread rain over the Northeastern States. Scattered rain would occur over Konkan, Goa, north interior Karnataka, Tamil Nadu, Rayalaseema and rest of east India. It will be isolated over the rest of Maharashtra, Andhra Pradesh and central India.

Pakistan

No monsoon low pressure is in sight that could bring pre-monsoon rainfall in Sindh and Karachi, though its too early for such things to happen in May but they will start from July.

There should be some monsoon depressions in the Bay of Bengal that needs to travel from India to Sindh, but this year Bay of Bengal is unusually not producing any depression it should have given birth to a cyclone uptill now. 98% monsoon rainfall of Karachi are from Bay of Bengal while 2% from Arabian sea.

It is June 2, and the leading edge of the SW Monsoon has reached northward into Karnataka state in southern India, according to the India Meteorology Department (IMD). Thus, all of Kerala and nearly all of Tamil Nadu have now witnessed the Monsoon onset. Timing is on schedule to a few days early, IMD maps show.

Not uncommonly, the Monsoon onset is raucous, being fraught with very heavy falls of rain, strong thunderstorms and even cyclonic disturbances of tropical storm strength.

Such a cyclone disturbance seems to be gathering at the writing near the Karnataka coast, site of the current SW Monsoon advance.
The June 2, 1200 UTC, run of the GFS numerical forecast model, to choose one such forecast tool, shows slow evolution of a significant center of low pressure along the Western Ghats of Karnataka and southern Maharashtra Friday through Sunday.

Then, early next week, this forecast scenario shows a well marked low, maybe having tropical storm strength winds, slipping off shore near Mumbai Tuesday or Wednesday.

Taken literally, the scenario suggests a tropical cyclone landfall on the Kathiawar Peninsula of Gujarat state about next Thursday.

WHAT WOULD BE THE IMPACT OF SUCH A WEATHER SYSTEM?

It should be made clear that the above scenario is even that–a scenario. Other forecast models and other runs of the GFS have shown different scenarios of timing and track. The June 2, 1200 UTC, NOGAPS forecast model has no significant low.

Anyways, I foresee further refining of the scenario going forward, with no assurance that a tropical cyclone or well-marked tropical low will take shape.
This said, the above scenario holds some threats to like and property in western India.

One such threat would be that of very heavy falls of rain potentially yielding flooding. It seems reasonable to me that amounts will reach 30 to 60 cm (about 12 to 24 inches) between the Arabian Sea coast and the Western Ghats. I would not rule out amounts of 90 cm (about 3 feet) by the middle of next week.
Winds of damaging potential would naturally hinge upon the intensity of the low.

The present GFS scenario would bring potentially damaging winds from near-shore waters to the Western Ghats, mostly in Maharashtra and Gujarat.

Other forecast scenarios have suggested a more open-water track aimed northwestward south of Kathiawar and Pakistan. As I see things, it is too early to rule out such a track.

GONU WAS ACTIVE FOUR YEARS AGO

As I understand it, Super Cyclonic Storm Gonu was the strongest such storm known to happen in the Arabian Sea. I believe that highest sustained 1-minute winds (JTWC) were 150 mph–equivalent to a upper rank Category 4 Atlantic hurricane. Super Cyclonic Storm Gonu east of Oman on June 4, 2007. NASA Image/Jeff Schmaltz

Gonu formed off western India on June 1, 2007, then deepened explosively westward over the open Arabian Sea. Its devastating landfall happened on June 5 over easternmost Oman, becoming what has been called the Arabian nation’s worst natural disaster. And it was the strongest such storm known to strike the Arabian Peninsula, as I understand it.

A second, last landfall took place from the Gulf of Oman in southeastern Iran, with further deadly effect.

The southwest monsoon made a decisive move forward on Thursday when it covered the entire south Arabian Sea, Kerala, Tamil Nadu, south Bay of Bengal and parts of central Arabian Sea, south Karnataka, Rayalaseema and parts of central Bay of Bengal.

An India Meteorological Department (IMD) update said that the northern limit passed through Udipi, Chitradurga, Arogyavaram and Chennai.

It assessed that conditions as favourable for its further advance into more parts of Arabian Sea, Karnataka, Andhra Pradesh, entire central Bay of Bengal and parts of south Maharashtra, the Northeastern States and north Bay of Bengal over the weekend.

A satellite picture showed convective (rain-bearing) clouds rising over parts of Assam, Chhattisgarh, Jharkhand, Orissa, south Maharashtra, south peninsular India, Lakshadweep, central and south Arabian Sea, central and south Bay of Bengal and the Andaman Sea. A weather warning valid until Sunday issued by the IMD said that heavy to very heavy rainfall would occur at a few places over coastal Karnataka and Kerala.

It will be isolated heavy over Lakshadweep, Andaman and Nicobar Islands, south Konkan and Goa during this period.

Meanwhile, the offshore trough representing the active status of monsoon lay extended from south Konkan to Kerala coast.

The upper air cyclonic circulation has slight shifted bearing to the west and was traced to over south and adjoining east-central Arabian Sea off Kerala and Karnataka.

Meanwhile, the European Centre for Medium-Range Weather Forecasting (ECWMF) has ramped up its forecast of evolving weather system in the sea to that of a full-scale tropical cyclone.

The system is forecast to take shape just off the Konkan coast by Monday, the ECMWF said, and would see gradual intensification with strengthening of flows.

It would act as the pivot around which the flows would rally, even helping open a window in the Bay of Bengal in the form of a likely low-pressure area. This would likely herald monsoon rains into the east coast and into central India. At the same time, the brewing cyclone would intensify and move a little away to the west-northwest and within striking distance of the southwest Gujarat coast.

GUJARAT TARGET?

In this manner, the monsoon would have been launched all along the west coast, including Konkan, Mumbai and even the Gujarat coast.

The cyclone system, meanwhile, would launch itself on a track further away from the Gujarat coast and head towards the Gulf of Eden.

Eventually, by June 10 up to which ECMWF forecast was available, it is shown as weakening a bit and loitering in the seas close to Oman.

The 10-day outlook given out by the Australian Bureau of Meteorology sought to concur with ECMWF in terms of initiation of the storm and expected track of movement.

Interestingly, the Taiwanese Central Weather Bureau on Thursday re-adjusted the track to being west-northwest and aiming towards the Gulf of Eden.

But it would have taken a hard swipe at extreme southwest coast of Gujarat before re-curving and weakening. It would then meander towards the Gulf of Eden region, the forecast said.